Abstract: The left lateral characteristics of Daquan fault was confirmed by: 1) remote sense images of the left-distortional drainage system; 2) statistics of scratches on the fault plane and cleavages in the fault zone; 3) micro-characteristics of fault rocks. ESR age of fault gouge indicated the fault movement occurred in early Pleistocene (1.2-1.5 Ma), whereas the branch faults movement occurred in ca. 300 ka. These data support that the formation of Daquan fault is closely related to the uplift process of Tibet, meanwhile it is also a long-distance effect of the continuous collision between Indian and Eurasia Plate and the uplift of Tibet during late Cenozoic.

Key words: Beishan area, ESR dating, strike-slip movement, Daquan fault

摘要： 卫星图片显示穿过大泉断裂的水系有被左行扭曲的特征，结合野外断层面上擦痕、断裂带中劈理观测统计和室内对断层岩显微构造的分析，确定了大泉断裂是以左行为主的走滑断裂带。对断层泥的ESR年代学测定，确定了大泉断裂开始活动时间为早更新世1.2～1.5Ma，其分支断层的活动时间在晚更新世300ka左右。大泉断裂活动时间与青藏高原在上新世末-早更新世初开始强烈隆升时间一致,表明大泉断裂的形成与青藏高原的隆升过程密切相关,是晚新生代印度和欧亚两大板块持续碰撞挤压和青藏高原隆升的远程效应。

关键词: 北山地区, ESR测年, 走滑活动, 大泉断裂